Arthropoda - Insecta - Lice

Question 1

5 Orders in Insecta

Answer 1

1. Phthiraptera (lice)
2. Hemiptera (true bugs)
3. Siphonaptera (fleas)
4. Hymenoptera (bees, wasps, ants, etc)
5. Diptera (flies and mosquitoes - have 2 wings)

Question 2

2 Suborders of Phthiraptera

Answer 2

1. Mallophaga (chewing lice - animals - triangle shaped head because lots of muscles)
2. Anoplura (sucking lice - humans)

Question 3

Anoplura morphological features

Answer 3

Feed on blood of their host - mouthparts consits of 3 piercing stylets - very specialized and difficult to homologize with other sucking insects
Stylets protrude from a rostrum (which is eversible)

Question 4

Phthiraptera undergo which type of metamorphosis?

Answer 4

Simple!

Eggs hatch, developing louse goes through 3 nymphal instars in most species

Question 5

3 Species of sucking lice

Answer 5

Pediculus humanus capitis (head louse)
Pediculus humanus humanus (body louse - only one that transmits disease)
Phthirus pubis (crab louse)
These subspecies do NOT breed

Question 6

Treatment of head lice

Answer 6

Pediculus humanus capitis
Wash hair with shampoo containing 1% benzene hexachloride)
Apply a mixture of pyrentins and pipronyl butoxide or copper oleate may be as effective and less toxic

Question 7

2 Diseases body louse can be vectors for

Answer 7

1. Epidemic typhus (Rickettsia prowazekii)

2. Louse-borne relapsing fever (Borrelia recurrentis)

Question 8

Louse-borne relapsing fever

Answer 8

Borrelia recurrentis
Pediculus humanus is vector
More severe than tick borne
Symptoms: jaundice, change in mental status, bleeding
Human scratches feces containing bacteria into the bite

Question 9

Phthrius pubis

mode of transmission and treatment

Answer 9

Usually transmitted by sexual contact

Same treatment as head - but also ointments with physostigmine or yellow mercury oxide